This application relates to wafer bonding. More specifically, and without limitation, to bonding semiconductors to create an optical device. Advanced electronic functions (e.g., photonic device bias control, modulation, amplification, data serialization and de-serialization, framing, and routing) are sometimes deployed on silicon integrated circuits. One reason for this is the presence of a global infrastructure for the design and fabrication of silicon integrated circuits that enables the production of devices having very advanced functions and performance at market-enabling costs. Silicon has not been useful for light emission or optical amplification due to its indirect energy bandgap.
Compound semiconductors (e.g., indium phosphide, gallium arsenide, and related ternary and quaternary materials) have been used for optical communications, and in particular for light emitting devices and photodiodes because of their direct-energy bandgap. However, integration of advanced electrical functions on these materials has been limited to niche, high-performance applications due to higher costs of fabricating devices and circuits in these materials. Further, integration of ternary and quaternary materials with silicon is challenging because of lattice mismatch between materials.